Absorbent product



Dec. 13, 1960 I w. H. ASHTON ETAL ABSORBENT PRODUCT 2 Sheets-Sheet 1Filed July 23 1956 Dec. 13, 1960 w. H. ASHTON EIAL 2,964,040

ABSORBENT PRODUCT Filed July 23, 1956 2 Sheets-Sheet 2 INV yoga gr M144J 0 5411419014. M255 TTO NEY.

ABSORBENT PRODUCT William H. Ashton, Philadelphia, Pa., and Edward A.Morse, Rahway, NJ, assignors to Personal Products Corporation, acorporation of New Jersey Filed July 23, 1956, Ser. No. 599,407

16 Claims. (Cl. 128-290) This invention relates to sanitary napkins andmore particularly to sanitary napkins of improved form and of improvedfluid absorbency and fluid retentivity characteristics.

Conventional sanitary napkins are generally rectangular in shape andinclude an elongated core of absorbent fibrous material covered with afluid permeable wrapper whose ends extend beyond the ends of the core toprovide tabs for securing the napkin in position on the body of thewearer. Since these napkins are of a flat, rectangular shape, itis'necessary that, in use, they be bent transversely into a curved shapeto conform them to the contours of the female pubic area. In addition,because the napkin is generally wider than the space between the legsadjacent the female pubic region, the napkin generally becomeslongitudinally folded with the edge portions of the napkin extendingdownwardly.

The dimensions of the pad portion of a typical conventional napkin areapproximately three-quarters of an inch thick by two and three-quartersinches wide by seven and one-half inches long. In actual use, however,the napkin does not retain its original form because it is necessary toforce the flat-shaped pad into one of an arcuate shape to conform it tothe curvature of the body area. In so bending the pad, a series ofcorrugations and folds are formed on the napkin surface adjacent thebody. These corrugations and ridges prevent the desired intimate contactbetween the napkin and that portion of the body of the wearer where asnug fit is necessary for proper functioning of the napkin. In addition,to cause the flat napkin of conventional form to assume an arcuate shapeand to retain such shape, tension must be applied to the sanitary beltto which the napkin is customarily attached. This produces discomfort.

The fluid retentivity and absorption characteristics of conventionalnapkins also are affected by the requirement that the napkin bedistorted to fit the female pubic area. Distorting the napkin results incompression of certain portions thereof, thereby reducing the ability ofthe napkin, and particularly the compressed portions, to absorb andretain fluid and often causing absorbed fluid to be squeezed out, thuswetting adjacent body surfaces.

In accordance with this invention, there is provided a sanitary napkinhaving a stabilized arcuate shape generally approximating the arcuateshape of the exterior female pubic area to which it is applied, therebypermitting the napkin to be worn comfortably. It is not required, aswith napkins of conventional shape, to distort the napkin of theinvention to make it conform to the configuration of the pubic area. Thelongitudinal and transverse corrugations and ridges resulting fromdeforming conventional napkins are avoided. An additional advantage ofthe napkin resides in its fluid absorbency and retentivitycharacteristics. The napkin of the invention contemplates interiorconstructions which confine absorbed fluid to a selected area and impedeits penetrating through to the sides and the lower surface of thenapkin. The napkin of the invention also includes exterior tes Patentconstructions which provide softness, thereby .nn'nimizing irritationwhich may arise due to rubbing and chafing, thus making the napkin morecomfortable to wear. The napkin also includes improvements relating toattaching it in position.

In the accompanying drawings:

Fig. 1 is a side view of the napkin illustrating the position of asuitable pinning strip for attaching the napkin;

Fig. 2 is a view of the napkin of Fig. 1 as seen from above;

Fig. 3 is an isometric view of the napkin, cut away to reveal its innerconstruction;

Figs. 4, 5 and 6 are sectional views on an enlarged scale of Fig. 1taken in the direction of planes 7, 8 and 9, respectively;

Fig. 7 is a top view of a multi-ply pad from which the napkin may beformed;

Fig. 8 is a side elevation of the pad of Fig. 7; and

Fig. 9 is an isometric view of the pad illustrated in Figs. 7 and 8,showing the manner in which the pad may be formed prior to being formedinto a napkin.

Referring to the drawings, there is shown a napkin 10, generally of anelongated shape to cover the area between the labia majora and the anus,having front and rear ends it and 12 respectively which are relativelybroad in Width, as best seen in Figs. 4 and 6, .and a center portion 13which is somewhat narrower, as shown in the section in Fig. 5. Bytapering the. napkin inwardly from the ends toward the center, thenapkin will fit comfortably between the legs and buttocks. The centerportion of the napkin is thicker than the end port-ions to providemaximum absorbency in the region where it is needed. In thickness, theend portionsof the napkin are, as seen in Fig. l, tapered so that theends will lie flat against the body and merge smoothly with adjacentbody surfaces to eliminate bulges. Preferably, the front end is slightlythicker than the rear end.

The napkin has an arcuate shape approximating that of the exteriorfemale pubic area Where .it is positioned, thereby eliminating theformation of ridges and corrugations, especially in the transversedirection as has been experienced heretofore with conventional napkins.By providing the napkin with such arcuate shape, the napkin can beplaced in intimate contact with the body without resorting todeformation of the napkin, as required with conventional napkins.

To secure the napkin in position for use, a pinning or carrier strip 14is attached to the bottom of and extended beyond the ends of the napkinto provide front and rear attach-ing tabs 15 and 16. The pinning stripmay be any of the materials found suitable heretofore possessingsulficient strength to bear the stresses imposed during use. Pinningstrips of gauze or a nonwoven fabric are satisfactory. The strip may beadhesively secured throughout the entire length of the napkin or only atthe ends 11 and 12 thereof.

To provide fluid absorbency and to retain fluid in the interior, thenapkin is provided with an elongated core 17 of absorbent fibers, suchas comminuted wood pulp fibers, disposed in the center and preferablyextending throughout substantially the entire length of the napkin.Other fibers may be used, such-as cotton linters, rag waste andabsorbent cotton, but cornniinuted wood pulp fibers are preferredbecause they are highly absorbent, inexpensive and readily available. Toconfine absorbed fluid in the interior of the napkin, the bottom surfaceand longitudinal edges of the absorbent core are covered with a waterrepellent film or'layer 18. As fluid strikes the upper surface ofnthenapkin,

it penetrates rapidly into the interior, whereupon it is retained andconfined in the absorbent core due to the water repellent layer 18. Thearea on the surface of the napkin upon which fluid normally impinges issmall compared to the overall surface area of the napkin with the result.that'the napkin becomes saturated rapidly in the moistened area. Whenthis occurs, fluid contacting the water repellent layer is spread in theabsorbent core towards the end of the napkin, thereby more fullyutilizing the absorbing effectiveness of the core. The water repellentlayer also prevents fiuid absorbed by the napkin from striking throughto the sides and bottom of the napkin and wetting adjacent bodysurfaces. A film of polyethylene approximately two mils in thickness hasbeen found particularly suitable. Other Water repellent materials may beused, such as paper treated to make it water repellent, to provide thebarrier effect. By using a film of polyethylene or similar thermoplasticmaterial to provide the fluid barrier in the interior of the napkin,added form stability of the napkin may be obtained. Polyethylene, andlike thermoplastic materials, soften when heat is applied and, whensoftened, may be molded into other shapes. One method of making thenapkin of the invention described below includes heating of thepolyethylene film during the forming stage in which event the filmcontributes to the structural stability of the napkin.

The core of absorbent fibers and the water repellent film are envelopedby a relatively thick outer fibrous layer 19, preferably containingabsorbent fibers, to impart softness to the napkin so that it may becomfortably worn. Outer layer 19 is made sufficiently thick and fluifyto cover the absorbent core 17 and the water repellent film 18 toprevent the film from contacting the body and causing irritation due tochafing and rubbing.

The napkin has an outer wrapper 20 of a fluid pervious material whichpreferably conforms closely to the shape of the napkin. Stockinetmaterial made of cotton or rayon yarn has been found particularlysuitable as an outer wrapper in that it is of an open mesh structure,thereby permitting fluid to pass through readily, and is extensible andelastic, thereby permitting it to stretch, or contract, as necessary, toconform to the configuration of the napkin. The absorbent portion of thenapkin may be placed into a tube of such stockinet material Whose lengthis slightly longer than the length of the absorbent portion of thenapkin, and the ends 21 of the stockinet material tucked under thebottom surface of the napkin adjacent the ends 11 and 12, as illustratedin Figs. 1 and 2. The adhesive material used to attach the pinning stripto the underside of the napkin may also be used to attach the foldedends of the stockinet wrapper in position. Other fluid perviousmaterials may be used if desired, such as knitted fabrics, woven fabricsor nonwoven fabrics. Knitted fabrics, or fabrics possessing similarextensibility characteristics, are preferred because they can be made toconform to the napkin shape to provide a smooth surface, free of foldsand wrinkles.

As has been experienced with conventional napkins, the efficiency of anapkin and the protection it provides will be unsatisfactory if thenapkin is not maintained in intimate contact with the body. To obtainthe desired intimate contact with conventional napkins, it has beennecessary to deform the napkin to the shape of the pubic area byapplying tension to the belt to which the napkin is attached. Thetension required often causes the belt to slide on the body and producesdiscomfort. By positioning the pinning strip 14 on the bottom of thenapkin and extending it along its length and beyond the ends thereof toprovide the attaching tabs, at better suspension of vtlhe napkin and amore comfortable, intimate fit between the napkin and the body isobtained. When a napkin having a pinning strip so located is attached toa belt or otherwise secured in position, the forces exerted on thepinning tabs 15 and 16 are distributed through the pinning strip to theunderside of the napkin. By underslinging the napkins pinning strip inthis manner, the napkin can be held in intimate contact with theadjacent body surfaces so that the advantages present in the napkin dueto its configuration and construction will be fully utilized. r

The napkin of the invention is structurally stabilized in that itretains its arcuate shape without support. Structural stability may beobtained by' incorporating into the napkin fibers which are heat orsolvent activatable with fibers which are nonactivatable. Thenonactivatable fibers, preferably absorbent cotton or rayon, arehomogeneously mixed with the fibers which are heat or solventactivatable. Other satisfactory nonactivatable fibers include Wood pulpfibers, absorbent paper tissue and mixtures thereof.

The activatable fibers include fibers which fuse or tackify when heatisapplied or when treated with solvents, such as the copolymer of vinylchloride and vinyl acetate, polyvinyl chloride, cellulose ethers oresters such as cellulose acetate. To supplement and facilitate theaction of the heat and/or solvent on the activatable fibers, a suitableplasticizer is generally incorporated. For cellulose acetate fibers,dimethyl phthalate mixtures of ortho and para-N-ethyl-toluenesulfonamide and methyl phthaL yl-ethyl glycollate are satisfactoryplasticizers and may be added in amounts of from about 10 to about 40percent or amounts sufficient to tackify the fibers under activatingconditions. The required activation of cellulose acetate fibers havingthe foregoing amounts of plasticizer content may be obtained by heatingthe fibers to a temperature of from about 140 to about 330 F.

The activatable materials need not necessarily be of the type which fuseor tackify when heated. Materials, such as the polyam-ides, polyesters,polyacrylates and heat settable vinyl polymer fibers, which shrink whenheated, may also be used. Further, nonactivatable fibers, such as cottonor rayon fibers, may be coated with a solu tion or an emulsion of athermoplastic or thermosetting resin of the type described above,thereby providing fibers which may be activated to form the napkin.These coated fibers may be mixed with untreated nonactivatable fibers.

To obtain the mechanical strength desired to impart structural stabilityto a napkin containing thermoplastic fibers, such as the copolymer ofvinyl chloride and vinyl acetate, the range by Weight of such fibers maybe from about 15 to about 40 percent and the remaining amountsconsisting of cotton or rayon. However, smaller amounts of thermoplasticfibers may be effective, particularly when used in conjunction with abonding resin. In the interest of economy, inasmuch as activatablefibers are generally more costly, the copolymer of vinyl chloride andvinyl acetate is maintained preferably to about 25 percent.Incorporating greater amounts of such fibers does not ordinarily providea napkin whose strength is markedly superior and may affect theabsorbing properties of the napkin.

Structural stability may also be imparted to the napkin in other ways.For example, the napkin may be sprayed with a suitable bonding resin,such as polyvinyl alcohol dispersed in Water, and then molded to thedesired shape by heating to activate the resin.

The napkin of the invention may be prepared from a multi-ply structureof the type illustrated in Figs. 7, 8 and 9. The laminate consists ofthe thick, fiuify, fibrous bottom layer 19, approximately eight andone-half inches wide, ten and one-half inches long and Weighing fromabout five to six grams, of carded homogeneously mixed fibers ofabsorbent cotton or rayon and suitable heat or solvent activatablefibers, such as that of the copolymer of vinyl chloride and vinylacetate. The layer contains about 75 percent absorbent cotton or rayonand 25 percent of the vinyl copolymer. The thin sheet of polyethylenefilm 18, about two mils thick, three and onehalf inches wide and six andthree-quarters inches long, is placed centrally upon the upper surfaceof the layer of fibers 19. The thick layer of absorbent fibers 17, suchas disintegrated wood pulp fibers weighing about six grams which formsthe core of the napkin, is then placed upon the polyethylene film 18.The layer may be about the same length as the ployethylene film uponwhich it is placed, and approximately two inches wide.

After the laminate has been formed, the longitudinal edges 22 and 23 ofthe bottom layer of fibers 19 are brought upwardly around thepolyethylene film and fibrous absorbent core and overlapped on the topsurface thereof, as seen in Fig. 9, thus enveloping the polyethylenefilm and absorbent core. In bringing the longitudinal edges of thefibrous layer up around the film and core and overlapping the edges ontop, the longitudinal edges 24 and 25 of the polyethylene film are alsobrought upward along the adjacent sides of the edges of the absorbentcore, thus covering the absorbent core on the bottom and side edges. Thelaminate is then heated dielectrically to heat the interior of thelaminate until the polyethylene film starts to soften and the wood pulpfibers adjacent the film begin to adhere to it. It is nextplaced into amold heated to 220 F. of the desired configuration and the mold closedand heated, or otherwise operated to produce the desired activation ofthe activatable fibers, to form the napkin into the stabilized arcuateshape. As the mold is closed, suitable cutting devices may beincorporated with the mold to cut the ends of the laminate during themold closing .operation. After the napkin has been molded into thedesired form, it is removed from the mold, covered with the wrapper 20and the pinning strip 14 attached to complete the napkin.

While in the foregoing there has been shown and described anillustrative embodiment of the invention, it is to be understood thatchanges in the details of construction, combinations and arrangements ofthe parts may be resorted to without departing fiom the scope and spiritof the invention.

We claim:

1. A sanitary napkin comprising absorbent material, said napkin havingapreformed acruate shape approximating that of the exterior female pubicarea to cover said area from forward of the labia majora to the anus,said napkin being tapered inwardly from a relatively greater width atits ends to a relatively smaller width at its center to fit comfortablyin said area, said napkin having an elongated absorbent core, a waterrepellent layer covering the bottom and sides of said core, a softfibrous layer enveloping said repellent layer and core, said fibrouslayer containing a .bonding agent bonding said fibers to structurallystabilize said napkinin said arcuate shape, a fluid pervious outerwrapper, and a pinning strip secured to the underside of said napkin andextending beyond the ends thereof to provide tabs for attaching saidnapkin.

'2. A sanitary napkin comprising absorbent material, said napkin havinga preformed arcuate shape approximating that of the exterior femalepubic area to cover said area from forward of the labia majora to theanus, said napkin tapering iwnardly from a relatively greater width atits ends to a relatively smaller width at its center to fit comfortablyin said area, said napkin having an elongated absorbent fibrous core, alayer of water repellent plastic material covering the bottom and sidesof said core, a soft layer of absorbent fibrous material enveloping saidfilm and core, said fibrous layer containing a bonding agent bondingsaid fibers to structurally stabilize said napkin in said arcuate shape,an outer wrapper of stockinet material, and a pinning strip of nonwovenfabric secured to the underside of said napkin and extending beyond theends thereof to provide tabs for attaching said napkin.

3. A sanitary napkin comprising absorbent material,

said napkin having a preformed arcuate shape approximating that of theexterior female pubic area to cover said area from forward of the labiamajora to the anus, said napkin being tapered inwardly from a relativelygreater width at its ends to a relatively smaller width at its center tofit comfortably in said area, said napkin having an elongated absorbentcore, a water repellent layer covering the bottom and sides of saidcore, a soft fibrous layer containing bonded activatable fibersenveloping said repellent layer and core, a fluid pervious outerwrapper, and a pinning strip secured to the underside of said napkin andextending beyond the ends thereof to provide tabs for attaching saidnapkin, said napkin being structurally stabilized in said arcuate shape.

4. A sanitary napkin according to claim 3 wherein said activatablefibers are thermoplastic fibers.

5. A sanitary napkin comprising absorbent material, said napkin having apreformed arcuate shape approximating that of the exterior female pubicarea to cover said area from forward of the labia majora to the anus,said napkin tapering inwardly from a relatively greater width at itsends to a relatively smaller width at its center to fit comfortably insaid area, said napkin having an elongated absorbent core of wood pulpfibers, a water repellent thermoplastic film covering the bottom andsides of said core, a soft layer of absorbent fibrous materialcontaining bonded activatable fibers enveloping said film and core, anouter wrapper of fluid pervious, conforming material, and a pinningstrip secured to the underside of said napkin and extending beyond theends thereof to provide tabs for attaching said napkin, said napkinbeing structurally stabilized in said arcuate shape.

6. A sanitary napkin comprising absorbent material, said napkin having apreformed arcuate shape approximating that of the exterior female pubicarea to cover said area from forward of the labia majora to the anus,said napkin tapering inwardly from a relatively greater width at itsends to a relatively smaller width at its center to fit comfortably insaid area, said napkin having an elongated core of wood pulp fibers, athin water repellent plastic film covering the bott-"m and sides of saidcore, a thick, soft layer of absorbent fibers and bonded activatablefibers enveloping said film and core, an outer wrapper of stockinetmaterial, and a fabric pinning strip secured to the underside of saidnapkin and extending beyond the ends thereof to provide tabs forattaching said napkin, said napkin being structurally stabilized in saidarcuate shape.

7. A sanitary napkin comprising absorbent material, said napkin havingan arcuate shape approximating that of the exterior female pubic area tocover said area from forward of the labia majora to the anus, saidnapkin tapering inwardly from a relatively greater width at its ends toa relatively smaller width at its center to fit comfortably in saidarea, said napkin-having an elongated absorbent fibrous core, a thinpolyethylene film covering the bottom and sides of said core, a softlayer comprising from about to about 60 percent by Weight of absorbentfibers and from about 15 to about 40 percent by weight of vinylchloride-vinyl acetate fibers enveloping said film and core, an outerwrapper of fluid pervious conforming fabric, and a pinning stripattached to the underside of said napkin and extending beyond the endsthereof to provide tabs for attaching said napkin, said napkin beingstructurally stabilized in said arcuate shape.

8. A sanitary napkin comprising absorbent material, said napkin havingan arcuate shape approximating that of the exterior female pubic area tocover said area from forward of the labia majora to the anus, saidnapkin tapering inwardly from a relatively greater width at its ends toa relatively smaller width at its center to fit comfortably in saidarea, said napkin having an elongated absorbent core of wood pulpfibers, a thin polyethylene film covering the bottom and sides of saidcore, a soft layer comprising from about 85 to about 60 percent byweight of absorbent fibers and from about to about 40 percent by weightof vinyl chloride-vinyl acetate fibers enveloping said film and core, anouter wrapper of stockinet material, and a pinning strip attached to theunderside of the napkin and extending beyond the ends thereof to providetabs for attaching said napkin, said napkin being structurallystabilized in said arcuate shape.

9. A sanitary napkin comprising absorbent material, said napkin having apreformed arcuate shape approximating that of the exterior female pubicarea to cover said area from forward of the labia majora to the anus,said napkin being tapered inwardly from a relatively greater width atits ends to a relatively smaller width at its center to fit comfortablyin said area, said napkin having an elongated absorbent core, a waterrepellent layer covering the bottom and sides of said core, a softfibrous layer of bonded fibers enveloping said repellent layer and core,and a fluid pervious outer wrapper, said napkin having tabs forattaching said napkin, said napkin being structurally stabilized in saidarcuate shape.

10. A sanitary napkin comprising absorbent material, said napkin havinga preformed arcuate shape approximating that of the exterior femalepubic area to cover said area from forward of the labia majora to theanus, said napkin being tapered inwardly from a relatively greater widthat its ends to a relatively smaller width at its center to fitcomfortably in said area, said napkin having an elongated absorbentcore, a water repellent layer covering the bottom and sides of saidcore, a soft fibrous layer enveloping said repellent layer and core, anda fluid pervious outer wrapper, said napkin having tabs for attachingsaid napkin, said fibrous layer containing a bonding agent bonding saidfibers to structurally stabilize said napkin in said arcuate shape.

11. A sanitary napkin comprising absorbent material, said napkin havinga preformed arcuate shape approximating that of the exterior femalepubic area to cover said area from forward of the labia majora to theanus, said napkin tapering inwardly from a relatively greater width atits ends to a relatively smaller width at its center to fit comfortablyin said area, said napkin having an elongated absorbent fibrous core, alayer of water repellent plastic material covering the bottom and sidesof said core, a soft layer of absorbent fibrous material enveloping saidfilm and core, and a fluid pervious outer wrapper, said napkin havingtabs for attaching said napkin, said fibrous layer containing a bondingagent bonding said fibers to structurally stabilize said napkin in saidarcuate shape.

12. A sanitary napkin comprising absorbent material, said napkin havinga preformed arcuate shape approximating that of the exterior femalepubic area to cover said area from forward of the labia maiora to theanus, said napkin being tapered inwardly from a relatively greater widthat its ends to a relatively smaller width at its center to fitcomfortably in said area, said napkin having an elongated absorbentcore, a water repellent layer covering the bottom and sides of saidcore, a soft fibrous layer enveloping said repellent layer and core, anda fluid pervious outer wrapper, said napkin having tabs for attachingsaid napkin, said napkin containing a bonding agent structurallystabilizing said napkin in said arcuate shape.

13. A sanitary napkin comprising absorbent material; said napkin havinga preformed arcuate shape approximating that of the exterior femalepubic area to cover said area from forward of the labia majora to theanus, said napkin being tapered inwardly from a relatively greater widthat its ends to a relatively smaller width at its center to fitcomfortably in said area, said napkin having an elongated absorbentcore, a water repellent layer covering the bottom and sides of saidcore, a soft fibrous layer enveloping said repellent layer and core, anda fluid pervious outer wrapper, said napkin having tabs for attachingsaid napkin, said napkin containing bonded activatable fibersstructurally stabilizing said napkin in said arcuate shape.

14. A sanitary napkin comprising absorbent material, said napkin havinga preformed arcuate shape approximating that of the exterior femalepubic area to cover said area from forward of the labia majora to theanus, said napkin having an elongated absorbent core, a water repellentlayer covering the bottom of said core, a soft fibrous layer envelopingsaid repellent layer and core, and a fluid pervious outer wrapper, saidnapkin having tabs for attaching said napkin, said fibrous layercontaining a bonding agent bonding said fibers to structurally stabilizesaid napkin in said arcuate shape.

15. A sanitary napkin comprising absorbent material, said napkin havinga preformed arcuate shape approximating that of the exterior femalepubic area to cover said area from forward of the labia majora to theanus, said napkin having an elongated absorbent core, a water repellentlayer covering the bottom of said core, a soft layer of absorbentfibrous material enveloping said repellent layer and core, and a fluidpervious outer wrapper, said napkin having tabs for attaching saidnapkin, said fibrous layer containing bonded activatable fibers tostructurally stabilize said napkin in said arcuate shape.

16. A sanitary napkin comprising absorbent material, said napkin havinga preformed arcuate shape approximating that of the exterior femalepubic area to cover said area from forward of the labia majora to theanus, said napkin having an elongated absorbent core, a water repellentlayer covering the bottom and sides of said core, a soft fibrous layerenveloping said repellent layer and core, and a fluid pervious outerwrapper, said napkin having tabs for attaching said napkin, said fibrouslayer containing bonded thermoplastic fibers to structurally stabilizesaid napkin in said arcuate shape.

References Cited in the file of this patent UNITED STATES PATENTS1,123,314 Kojima Jan. 5, 1915 1,192,439 Luellen July 25, 1916 1,222,899Smith Apr. 17, 1917 2,526,125 Francis Oct. 17, 1950 2,774,128 SecristOct. 24, 1950 2,549,982 McKahann et al. Apr. 24, 1951 2,566,325 GanzSept. 4, 1951 2,697,678 Ness et al Dec. 21, 1954 2,815,027 Makela Dec.3, 1957 FOREIGN PATENTS 352,805 Great Britain July 16, 1931

